1. Field of the Invention
The present invention relates to a method for producing a nitride single crystal.
2. Description of Related Art
Gallium nitride-based III-V nitride has been receiving a great deal of attention as a superior blue light emitting element, and has been practically used in material for light emitting diodes or semiconductor laser diodes. According to methods described in Patent Publications JP 2002-293696A, JP 2003-292400A, WO 2005/095682 A1 and WO 2006/030718 A1, a group-III nitride single crystal is grown by flux method. More specifically, a seed crystal substrate is placed in a uniformly heated flux to grow a single crystal.
JP 2004-231447A discloses that a significantly great temperature difference is established between a gas-liquid interface and a single crystal growing region when a nitride single crystal is grown. The temperature difference in a melt according to an example of this publication is 150° C. or greater.
Further, in JP 2005-154254A, the temperature difference inside a melt is set to 10° C. or greater but not greater than 300° C., and preferably 100° C. or greater but not greater than 200° C.
A method for growing a nitride semiconductor is disclosed in which the method is employed in conjunction with techniques of vibrating an apparatus and installing agitating blades inside a crucible for causing a flow travelling from a gas-liquid interface, where physical contact with a raw material gas is made, to the inside of the raw material liquid (JP 2005-263622A).
Another method for growing nitride is disclosed in which an auxiliary heater is mounted on a lower section of a stainless container to make a raw material uniform by means of thermal convection (TuP1-17, International Workshop on Nitride Semiconductors 2006 [IWN2006]).